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document regcomp.c/regexec.c's dual life under ext/re/
[perl5.git] / regexec.c
diff --git a/regexec.c b/regexec.c
index bdc05af..6a7f064 100644 (file)
--- a/regexec.c
+++ b/regexec.c
@@ -5,6 +5,17 @@
  * "One Ring to rule them all, One Ring to find them..."
  */
 
  * "One Ring to rule them all, One Ring to find them..."
  */
 
+/* This file contains functions for executing a regular expression.  See
+ * also regcomp.c which funnily enough, contains functions for compiling
+ * a regular expression.
+ *
+ * This file is also copied at build time to ext/re/re_exec.c, where
+ * it's built with -DPERL_EXT_RE_BUILD -DPERL_EXT_RE_DEBUG -DPERL_EXT.
+ * This causes the main functions to be compiled under new names and with
+ * debugging support added, which makes "use re 'debug'" work.
+ 
+ */
+
 /* NOTE: this is derived from Henry Spencer's regexp code, and should not
  * confused with the original package (see point 3 below).  Thanks, Henry!
  */
 /* NOTE: this is derived from Henry Spencer's regexp code, and should not
  * confused with the original package (see point 3 below).  Thanks, Henry!
  */
@@ -67,7 +78,8 @@
  *
  ****    Alterations to Henry's code are...
  ****
  *
  ****    Alterations to Henry's code are...
  ****
- ****    Copyright (c) 1991-2002, Larry Wall
+ ****    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
+ ****    2000, 2001, 2002, 2003, 2004, by Larry Wall and others
  ****
  ****    You may distribute under the terms of either the GNU General Public
  ****    License or the Artistic License, as specified in the README file.
  ****
  ****    You may distribute under the terms of either the GNU General Public
  ****    License or the Artistic License, as specified in the README file.
@@ -86,6 +98,7 @@
 #define RF_warned      2               /* warned about big count? */
 #define RF_evaled      4               /* Did an EVAL with setting? */
 #define RF_utf8                8               /* String contains multibyte chars? */
 #define RF_warned      2               /* warned about big count? */
 #define RF_evaled      4               /* Did an EVAL with setting? */
 #define RF_utf8                8               /* String contains multibyte chars? */
+#define RF_false       16              /* odd number of nested negatives */
 
 #define UTF ((PL_reg_flags & RF_utf8) != 0)
 
 
 #define UTF ((PL_reg_flags & RF_utf8) != 0)
 
@@ -171,7 +184,7 @@ S_regcppush(pTHX_ I32 parenfloor)
        Perl_croak(aTHX_ "panic: paren_elems_to_push < 0");
 
 #define REGCP_OTHER_ELEMS 6
        Perl_croak(aTHX_ "panic: paren_elems_to_push < 0");
 
 #define REGCP_OTHER_ELEMS 6
-    SSCHECK(paren_elems_to_push + REGCP_OTHER_ELEMS);
+    SSGROW(paren_elems_to_push + REGCP_OTHER_ELEMS);
     for (p = PL_regsize; p > parenfloor; p--) {
 /* REGCP_PARENS_ELEMS are pushed per pairs of parentheses. */
        SSPUSHINT(PL_regendp[p]);
     for (p = PL_regsize; p > parenfloor; p--) {
 /* REGCP_PARENS_ELEMS are pushed per pairs of parentheses. */
        SSPUSHINT(PL_regendp[p]);
@@ -396,10 +409,12 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
     I32 ml_anch;
     register char *other_last = Nullch;        /* other substr checked before this */
     char *check_at = Nullch;           /* check substr found at this pos */
     I32 ml_anch;
     register char *other_last = Nullch;        /* other substr checked before this */
     char *check_at = Nullch;           /* check substr found at this pos */
+    I32 multiline = prog->reganch & PMf_MULTILINE;
 #ifdef DEBUGGING
     char *i_strpos = strpos;
     SV *dsv = PERL_DEBUG_PAD_ZERO(0);
 #endif
 #ifdef DEBUGGING
     char *i_strpos = strpos;
     SV *dsv = PERL_DEBUG_PAD_ZERO(0);
 #endif
+    RX_MATCH_UTF8_set(prog,do_utf8);
 
     if (prog->reganch & ROPT_UTF8) {
        DEBUG_r(PerlIO_printf(Perl_debug_log,
 
     if (prog->reganch & ROPT_UTF8) {
        DEBUG_r(PerlIO_printf(Perl_debug_log,
@@ -456,7 +471,7 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
     if (prog->reganch & ROPT_ANCH) {   /* Match at beg-of-str or after \n */
        ml_anch = !( (prog->reganch & ROPT_ANCH_SINGLE)
                     || ( (prog->reganch & ROPT_ANCH_BOL)
     if (prog->reganch & ROPT_ANCH) {   /* Match at beg-of-str or after \n */
        ml_anch = !( (prog->reganch & ROPT_ANCH_SINGLE)
                     || ( (prog->reganch & ROPT_ANCH_BOL)
-                         && !PL_multiline ) ); /* Check after \n? */
+                         && !multiline ) );    /* Check after \n? */
 
        if (!ml_anch) {
          if ( !(prog->reganch & (ROPT_ANCH_GPOS /* Checked by the caller */
 
        if (!ml_anch) {
          if ( !(prog->reganch & (ROPT_ANCH_GPOS /* Checked by the caller */
@@ -541,17 +556,20 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
                            start_shift + (s - strbeg), end_shift, pp, 0);
        else
            goto fail_finish;
                            start_shift + (s - strbeg), end_shift, pp, 0);
        else
            goto fail_finish;
+       /* we may be pointing at the wrong string */
+       if (s && RX_MATCH_COPIED(prog))
+           s = strbeg + (s - SvPVX(sv));
        if (data)
            *data->scream_olds = s;
     }
     else if (prog->reganch & ROPT_CANY_SEEN)
        s = fbm_instr((U8*)(s + start_shift),
                      (U8*)(strend - end_shift),
        if (data)
            *data->scream_olds = s;
     }
     else if (prog->reganch & ROPT_CANY_SEEN)
        s = fbm_instr((U8*)(s + start_shift),
                      (U8*)(strend - end_shift),
-                     check, PL_multiline ? FBMrf_MULTILINE : 0);
+                     check, multiline ? FBMrf_MULTILINE : 0);
     else
        s = fbm_instr(HOP3(s, start_shift, strend),
                      HOP3(strend, -end_shift, strbeg),
     else
        s = fbm_instr(HOP3(s, start_shift, strend),
                      HOP3(strend, -end_shift, strbeg),
-                     check, PL_multiline ? FBMrf_MULTILINE : 0);
+                     check, multiline ? FBMrf_MULTILINE : 0);
 
     /* Update the count-of-usability, remove useless subpatterns,
        unshift s.  */
 
     /* Update the count-of-usability, remove useless subpatterns,
        unshift s.  */
@@ -595,7 +613,7 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
 
                t = s - prog->check_offset_max;
                if (s - strpos > prog->check_offset_max  /* signed-corrected t > strpos */
 
                t = s - prog->check_offset_max;
                if (s - strpos > prog->check_offset_max  /* signed-corrected t > strpos */
-                   && (!(prog->reganch & ROPT_UTF8)
+                   && (!do_utf8
                        || ((t = reghopmaybe3_c(s, -(prog->check_offset_max), strpos))
                            && t > strpos)))
                    /* EMPTY */;
                        || ((t = reghopmaybe3_c(s, -(prog->check_offset_max), strpos))
                            && t > strpos)))
                    /* EMPTY */;
@@ -620,7 +638,7 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
                        HOP3(HOP3(last1, prog->anchored_offset, strend)
                                + SvCUR(must), -(SvTAIL(must)!=0), strbeg),
                        must,
                        HOP3(HOP3(last1, prog->anchored_offset, strend)
                                + SvCUR(must), -(SvTAIL(must)!=0), strbeg),
                        must,
-                       PL_multiline ? FBMrf_MULTILINE : 0
+                       multiline ? FBMrf_MULTILINE : 0
                    );
                DEBUG_r(PerlIO_printf(Perl_debug_log,
                        "%s anchored substr `%s%.*s%s'%s",
                    );
                DEBUG_r(PerlIO_printf(Perl_debug_log,
                        "%s anchored substr `%s%.*s%s'%s",
@@ -681,7 +699,7 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
                s = fbm_instr((unsigned char*)s,
                              (unsigned char*)last + SvCUR(must)
                                  - (SvTAIL(must)!=0),
                s = fbm_instr((unsigned char*)s,
                              (unsigned char*)last + SvCUR(must)
                                  - (SvTAIL(must)!=0),
-                             must, PL_multiline ? FBMrf_MULTILINE : 0);
+                             must, multiline ? FBMrf_MULTILINE : 0);
            DEBUG_r(PerlIO_printf(Perl_debug_log, "%s floating substr `%s%.*s%s'%s",
                    (s ? "Found" : "Contradicts"),
                    PL_colors[0],
            DEBUG_r(PerlIO_printf(Perl_debug_log, "%s floating substr `%s%.*s%s'%s",
                    (s ? "Found" : "Contradicts"),
                    PL_colors[0],
@@ -715,7 +733,7 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
 
     t = s - prog->check_offset_max;
     if (s - strpos > prog->check_offset_max  /* signed-corrected t > strpos */
 
     t = s - prog->check_offset_max;
     if (s - strpos > prog->check_offset_max  /* signed-corrected t > strpos */
-        && (!(prog->reganch & ROPT_UTF8)
+        && (!do_utf8
            || ((t = reghopmaybe3_c(s, -prog->check_offset_max, strpos))
                 && t > strpos))) {
        /* Fixed substring is found far enough so that the match
            || ((t = reghopmaybe3_c(s, -prog->check_offset_max, strpos))
                 && t > strpos))) {
        /* Fixed substring is found far enough so that the match
@@ -848,10 +866,7 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
        char *startpos = strbeg;
 
        t = s;
        char *startpos = strbeg;
 
        t = s;
-       if (prog->reganch & ROPT_UTF8) {        
-           PL_regdata = prog->data;
-           PL_bostr = startpos;
-       }
+       cache_re(prog);
        s = find_byclass(prog, prog->regstclass, s, endpos, startpos, 1);
        if (!s) {
 #ifdef DEBUGGING
        s = find_byclass(prog, prog->regstclass, s, endpos, startpos, 1);
        if (!s) {
 #ifdef DEBUGGING
@@ -950,6 +965,8 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        I32 doevery = (prog->reganch & ROPT_SKIP) == 0;
        char *m;
        STRLEN ln;
        I32 doevery = (prog->reganch & ROPT_SKIP) == 0;
        char *m;
        STRLEN ln;
+       STRLEN lnc;
+       register STRLEN uskip;
        unsigned int c1;
        unsigned int c2;
        char *e;
        unsigned int c1;
        unsigned int c2;
        char *e;
@@ -959,25 +976,40 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        /* We know what class it must start with. */
        switch (OP(c)) {
        case ANYOF:
        /* We know what class it must start with. */
        switch (OP(c)) {
        case ANYOF:
-           while (s < strend) {
-               STRLEN skip = do_utf8 ? UTF8SKIP(s) : 1;
-                 
-               if (do_utf8 ?
-                   reginclass(c, (U8*)s, 0, do_utf8) :
-                   REGINCLASS(c, (U8*)s) ||
-                   (ANYOF_FOLD_SHARP_S(c, s, strend) &&
-                    /* The assignment of 2 is intentional:
-                     * for the sharp s, the skip is 2. */
-                    (skip = SHARP_S_SKIP)
-                    )) {
-                   if (tmp && (norun || regtry(prog, s)))
-                       goto got_it;
-                   else
-                       tmp = doevery;
-               }
-               else 
-                   tmp = 1;
-               s += skip;
+           if (do_utf8) {
+                while (s + (uskip = UTF8SKIP(s)) <= strend) {
+                     if ((ANYOF_FLAGS(c) & ANYOF_UNICODE) ||
+                         !UTF8_IS_INVARIANT((U8)s[0]) ?
+                         reginclass(c, (U8*)s, 0, do_utf8) :
+                         REGINCLASS(c, (U8*)s)) {
+                          if (tmp && (norun || regtry(prog, s)))
+                               goto got_it;
+                          else
+                               tmp = doevery;
+                     }
+                     else 
+                          tmp = 1;
+                     s += uskip;
+                }
+           }
+           else {
+                while (s < strend) {
+                     STRLEN skip = 1;
+
+                     if (REGINCLASS(c, (U8*)s) ||
+                         (ANYOF_FOLD_SHARP_S(c, s, strend) &&
+                          /* The assignment of 2 is intentional:
+                           * for the folded sharp s, the skip is 2. */
+                          (skip = SHARP_S_SKIP))) {
+                          if (tmp && (norun || regtry(prog, s)))
+                               goto got_it;
+                          else
+                               tmp = doevery;
+                     }
+                     else 
+                          tmp = 1;
+                     s += skip;
+                }
            }
            break;
        case CANY:
            }
            break;
        case CANY:
@@ -990,10 +1022,12 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
            }
            break;
        case EXACTF:
            }
            break;
        case EXACTF:
-           m = STRING(c);
-           ln = STR_LEN(c);
+           m   = STRING(c);
+           ln  = STR_LEN(c);   /* length to match in octets/bytes */
+           lnc = (I32) ln;     /* length to match in characters */
            if (UTF) {
                STRLEN ulen1, ulen2;
            if (UTF) {
                STRLEN ulen1, ulen2;
+               U8 *sm = (U8 *) m;
                U8 tmpbuf1[UTF8_MAXLEN_UCLC+1];
                U8 tmpbuf2[UTF8_MAXLEN_UCLC+1];
 
                U8 tmpbuf1[UTF8_MAXLEN_UCLC+1];
                U8 tmpbuf2[UTF8_MAXLEN_UCLC+1];
 
@@ -1004,6 +1038,11 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                                    0, ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY);
                c2 = utf8n_to_uvchr(tmpbuf2, UTF8_MAXLEN_UCLC,
                                    0, ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY);
                                    0, ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY);
                c2 = utf8n_to_uvchr(tmpbuf2, UTF8_MAXLEN_UCLC,
                                    0, ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY);
+               lnc = 0;
+               while (sm < ((U8 *) m + ln)) {
+                   lnc++;
+                   sm += UTF8SKIP(sm);
+               }
            }
            else {
                c1 = *(U8*)m;
            }
            else {
                c1 = *(U8*)m;
@@ -1011,12 +1050,13 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
            }
            goto do_exactf;
        case EXACTFL:
            }
            goto do_exactf;
        case EXACTFL:
-           m = STRING(c);
-           ln = STR_LEN(c);
+           m   = STRING(c);
+           ln  = STR_LEN(c);
+           lnc = (I32) ln;
            c1 = *(U8*)m;
            c2 = PL_fold_locale[c1];
          do_exactf:
            c1 = *(U8*)m;
            c2 = PL_fold_locale[c1];
          do_exactf:
-           e = HOP3c(strend, -(I32)ln, s);
+           e = HOP3c(strend, -((I32)lnc), s);
 
            if (norun && e < s)
                e = s;                  /* Due to minlen logic of intuit() */
 
            if (norun && e < s)
                e = s;                  /* Due to minlen logic of intuit() */
@@ -1039,6 +1079,8 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                STRLEN len, foldlen;
                
                if (c1 == c2) {
                STRLEN len, foldlen;
                
                if (c1 == c2) {
+                   /* Upper and lower of 1st char are equal -
+                    * probably not a "letter". */
                    while (s <= e) {
                        c = utf8n_to_uvchr((U8*)s, UTF8_MAXLEN, &len,
                                           ckWARN(WARN_UTF8) ?
                    while (s <= e) {
                        c = utf8n_to_uvchr((U8*)s, UTF8_MAXLEN, &len,
                                           ckWARN(WARN_UTF8) ?
@@ -1143,7 +1185,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                tmp = ((OP(c) == BOUND ?
                        isALNUM_uni(tmp) : isALNUM_LC_uvchr(UNI_TO_NATIVE(tmp))) != 0);
                LOAD_UTF8_CHARCLASS(alnum,"a");
                tmp = ((OP(c) == BOUND ?
                        isALNUM_uni(tmp) : isALNUM_LC_uvchr(UNI_TO_NATIVE(tmp))) != 0);
                LOAD_UTF8_CHARCLASS(alnum,"a");
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (tmp == !(OP(c) == BOUND ?
                                 swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8) :
                                 isALNUM_LC_utf8((U8*)s)))
                    if (tmp == !(OP(c) == BOUND ?
                                 swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8) :
                                 isALNUM_LC_utf8((U8*)s)))
@@ -1152,7 +1194,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                        if ((norun || regtry(prog, s)))
                            goto got_it;
                    }
                        if ((norun || regtry(prog, s)))
                            goto got_it;
                    }
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
                }
            }
            else {
@@ -1186,14 +1228,14 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                tmp = ((OP(c) == NBOUND ?
                        isALNUM_uni(tmp) : isALNUM_LC_uvchr(UNI_TO_NATIVE(tmp))) != 0);
                LOAD_UTF8_CHARCLASS(alnum,"a");
                tmp = ((OP(c) == NBOUND ?
                        isALNUM_uni(tmp) : isALNUM_LC_uvchr(UNI_TO_NATIVE(tmp))) != 0);
                LOAD_UTF8_CHARCLASS(alnum,"a");
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (tmp == !(OP(c) == NBOUND ?
                                 swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8) :
                                 isALNUM_LC_utf8((U8*)s)))
                        tmp = !tmp;
                    else if ((norun || regtry(prog, s)))
                        goto got_it;
                    if (tmp == !(OP(c) == NBOUND ?
                                 swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8) :
                                 isALNUM_LC_utf8((U8*)s)))
                        tmp = !tmp;
                    else if ((norun || regtry(prog, s)))
                        goto got_it;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
                }
            }
            else {
@@ -1215,7 +1257,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case ALNUM:
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS(alnum,"a");
        case ALNUM:
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS(alnum,"a");
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
                    if (swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1224,7 +1266,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
                }
            }
            else {
@@ -1244,7 +1286,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case ALNUML:
            PL_reg_flags |= RF_tainted;
            if (do_utf8) {
        case ALNUML:
            PL_reg_flags |= RF_tainted;
            if (do_utf8) {
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (isALNUM_LC_utf8((U8*)s)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
                    if (isALNUM_LC_utf8((U8*)s)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1253,7 +1295,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
                }
            }
            else {
@@ -1273,7 +1315,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case NALNUM:
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS(alnum,"a");
        case NALNUM:
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS(alnum,"a");
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (!swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
                    if (!swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1282,7 +1324,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
                }
            }
            else {
@@ -1302,7 +1344,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case NALNUML:
            PL_reg_flags |= RF_tainted;
            if (do_utf8) {
        case NALNUML:
            PL_reg_flags |= RF_tainted;
            if (do_utf8) {
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (!isALNUM_LC_utf8((U8*)s)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
                    if (!isALNUM_LC_utf8((U8*)s)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1311,7 +1353,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
                }
            }
            else {
@@ -1331,7 +1373,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case SPACE:
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS(space," ");
        case SPACE:
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS(space," ");
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (*s == ' ' || swash_fetch(PL_utf8_space,(U8*)s, do_utf8)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
                    if (*s == ' ' || swash_fetch(PL_utf8_space,(U8*)s, do_utf8)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1340,7 +1382,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
                }
            }
            else {
@@ -1360,7 +1402,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case SPACEL:
            PL_reg_flags |= RF_tainted;
            if (do_utf8) {
        case SPACEL:
            PL_reg_flags |= RF_tainted;
            if (do_utf8) {
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (*s == ' ' || isSPACE_LC_utf8((U8*)s)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
                    if (*s == ' ' || isSPACE_LC_utf8((U8*)s)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1369,7 +1411,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
                }
            }
            else {
@@ -1389,7 +1431,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case NSPACE:
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS(space," ");
        case NSPACE:
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS(space," ");
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (!(*s == ' ' || swash_fetch(PL_utf8_space,(U8*)s, do_utf8))) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
                    if (!(*s == ' ' || swash_fetch(PL_utf8_space,(U8*)s, do_utf8))) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1398,7 +1440,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
                }
            }
            else {
@@ -1418,7 +1460,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case NSPACEL:
            PL_reg_flags |= RF_tainted;
            if (do_utf8) {
        case NSPACEL:
            PL_reg_flags |= RF_tainted;
            if (do_utf8) {
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (!(*s == ' ' || isSPACE_LC_utf8((U8*)s))) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
                    if (!(*s == ' ' || isSPACE_LC_utf8((U8*)s))) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1427,7 +1469,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
                }
            }
            else {
@@ -1447,7 +1489,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case DIGIT:
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS(digit,"0");
        case DIGIT:
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS(digit,"0");
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (swash_fetch(PL_utf8_digit,(U8*)s, do_utf8)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
                    if (swash_fetch(PL_utf8_digit,(U8*)s, do_utf8)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1456,7 +1498,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
                }
            }
            else {
@@ -1476,7 +1518,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case DIGITL:
            PL_reg_flags |= RF_tainted;
            if (do_utf8) {
        case DIGITL:
            PL_reg_flags |= RF_tainted;
            if (do_utf8) {
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (isDIGIT_LC_utf8((U8*)s)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
                    if (isDIGIT_LC_utf8((U8*)s)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1485,7 +1527,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
                }
            }
            else {
@@ -1505,7 +1547,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case NDIGIT:
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS(digit,"0");
        case NDIGIT:
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS(digit,"0");
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (!swash_fetch(PL_utf8_digit,(U8*)s, do_utf8)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
                    if (!swash_fetch(PL_utf8_digit,(U8*)s, do_utf8)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1514,7 +1556,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
                }
            }
            else {
@@ -1534,7 +1576,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case NDIGITL:
            PL_reg_flags |= RF_tainted;
            if (do_utf8) {
        case NDIGITL:
            PL_reg_flags |= RF_tainted;
            if (do_utf8) {
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (!isDIGIT_LC_utf8((U8*)s)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
                    if (!isDIGIT_LC_utf8((U8*)s)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1543,7 +1585,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
                }
            }
            else {
@@ -1593,10 +1635,12 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
     char *scream_olds;
     SV* oreplsv = GvSV(PL_replgv);
     bool do_utf8 = DO_UTF8(sv);
     char *scream_olds;
     SV* oreplsv = GvSV(PL_replgv);
     bool do_utf8 = DO_UTF8(sv);
+    I32 multiline = prog->reganch & PMf_MULTILINE;
 #ifdef DEBUGGING
     SV *dsv0 = PERL_DEBUG_PAD_ZERO(0);
     SV *dsv1 = PERL_DEBUG_PAD_ZERO(1);
 #endif
 #ifdef DEBUGGING
     SV *dsv0 = PERL_DEBUG_PAD_ZERO(0);
     SV *dsv1 = PERL_DEBUG_PAD_ZERO(1);
 #endif
+    RX_MATCH_UTF8_set(prog,do_utf8);
 
     PL_regcc = 0;
 
 
     PL_regcc = 0;
 
@@ -1708,7 +1752,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
     if (prog->reganch & (ROPT_ANCH & ~ROPT_ANCH_GPOS)) {
        if (s == startpos && regtry(prog, startpos))
            goto got_it;
     if (prog->reganch & (ROPT_ANCH & ~ROPT_ANCH_GPOS)) {
        if (s == startpos && regtry(prog, startpos))
            goto got_it;
-       else if (PL_multiline || (prog->reganch & ROPT_IMPLICIT)
+       else if (multiline || (prog->reganch & ROPT_IMPLICIT)
                 || (prog->reganch & ROPT_ANCH_MBOL)) /* XXXX SBOL? */
        {
            char *end;
                 || (prog->reganch & ROPT_ANCH_MBOL)) /* XXXX SBOL? */
        {
            char *end;
@@ -1842,7 +1886,10 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
                                    end_shift, &scream_pos, 0))
                 : (s = fbm_instr((unsigned char*)HOP3(s, back_min, strend),
                                  (unsigned char*)strend, must,
                                    end_shift, &scream_pos, 0))
                 : (s = fbm_instr((unsigned char*)HOP3(s, back_min, strend),
                                  (unsigned char*)strend, must,
-                                 PL_multiline ? FBMrf_MULTILINE : 0))) ) {
+                                 multiline ? FBMrf_MULTILINE : 0))) ) {
+           /* we may be pointing at the wrong string */
+           if ((flags & REXEC_SCREAM) && RX_MATCH_COPIED(prog))
+               s = strbeg + (s - SvPVX(sv));
            DEBUG_r( did_match = 1 );
            if (HOPc(s, -back_max) > last1) {
                last1 = HOPc(s, -back_min);
            DEBUG_r( did_match = 1 );
            if (HOPc(s, -back_max) > last1) {
                last1 = HOPc(s, -back_min);
@@ -1882,9 +1929,12 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
        goto phooey;
     }
     else if ((c = prog->regstclass)) {
        goto phooey;
     }
     else if ((c = prog->regstclass)) {
-       if (minlen && PL_regkind[(U8)OP(prog->regstclass)] != EXACT)
+       if (minlen) {
+           I32 op = (U8)OP(prog->regstclass);
            /* don't bother with what can't match */
            /* don't bother with what can't match */
-           strend = HOPc(strend, -(minlen - 1));
+           if (PL_regkind[op] != EXACT && op != CANY)
+               strend = HOPc(strend, -(minlen - 1));
+       }
        DEBUG_r({
            SV *prop = sv_newmortal();
            char *s0;
        DEBUG_r({
            SV *prop = sv_newmortal();
            char *s0;
@@ -1926,6 +1976,9 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
                                   end_shift, &scream_pos, 1); /* last one */
                if (!last)
                    last = scream_olds; /* Only one occurrence. */
                                   end_shift, &scream_pos, 1); /* last one */
                if (!last)
                    last = scream_olds; /* Only one occurrence. */
+               /* we may be pointing at the wrong string */
+               else if (RX_MATCH_COPIED(prog))
+                   s = strbeg + (s - SvPVX(sv));
            }
            else {
                STRLEN len;
            }
            else {
                STRLEN len;
@@ -1934,7 +1987,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
                if (SvTAIL(float_real)) {
                    if (memEQ(strend - len + 1, little, len - 1))
                        last = strend - len + 1;
                if (SvTAIL(float_real)) {
                    if (memEQ(strend - len + 1, little, len - 1))
                        last = strend - len + 1;
-                   else if (!PL_multiline)
+                   else if (!multiline)
                        last = memEQ(strend - len, little, len)
                            ? strend - len : Nullch;
                    else
                        last = memEQ(strend - len, little, len)
                            ? strend - len : Nullch;
                    else
@@ -1993,17 +2046,28 @@ got_it:
 
     /* make sure $`, $&, $', and $digit will work later */
     if ( !(flags & REXEC_NOT_FIRST) ) {
 
     /* make sure $`, $&, $', and $digit will work later */
     if ( !(flags & REXEC_NOT_FIRST) ) {
-       if (RX_MATCH_COPIED(prog)) {
-           Safefree(prog->subbeg);
-           RX_MATCH_COPIED_off(prog);
-       }
+       RX_MATCH_COPY_FREE(prog);
        if (flags & REXEC_COPY_STR) {
            I32 i = PL_regeol - startpos + (stringarg - strbeg);
        if (flags & REXEC_COPY_STR) {
            I32 i = PL_regeol - startpos + (stringarg - strbeg);
-
-           s = savepvn(strbeg, i);
-           prog->subbeg = s;
+#ifdef PERL_COPY_ON_WRITE
+           if ((SvIsCOW(sv)
+                || (SvFLAGS(sv) & CAN_COW_MASK) == CAN_COW_FLAGS)) {
+               if (DEBUG_C_TEST) {
+                   PerlIO_printf(Perl_debug_log,
+                                 "Copy on write: regexp capture, type %d\n",
+                                 (int) SvTYPE(sv));
+               }
+               prog->saved_copy = sv_setsv_cow(prog->saved_copy, sv);
+               prog->subbeg = SvPVX(prog->saved_copy);
+               assert (SvPOKp(prog->saved_copy));
+           } else
+#endif
+           {
+               RX_MATCH_COPIED_on(prog);
+               s = savepvn(strbeg, i);
+               prog->subbeg = s;
+           }
            prog->sublen = i;
            prog->sublen = i;
-           RX_MATCH_COPIED_on(prog);
        }
        else {
            prog->subbeg = strbeg;
        }
        else {
            prog->subbeg = strbeg;
@@ -2054,8 +2118,7 @@ S_regtry(pTHX_ regexp *prog, char *startpos)
        if (PL_reg_sv) {
            /* Make $_ available to executed code. */
            if (PL_reg_sv != DEFSV) {
        if (PL_reg_sv) {
            /* Make $_ available to executed code. */
            if (PL_reg_sv != DEFSV) {
-               /* SAVE_DEFSV does *not* suffice here for USE_5005THREADS */
-               SAVESPTR(DEFSV);
+               SAVE_DEFSV;
                DEFSV = PL_reg_sv;
            }
        
                DEFSV = PL_reg_sv;
            }
        
@@ -2093,6 +2156,9 @@ S_regtry(pTHX_ regexp *prog, char *startpos)
                $` inside (?{}) could fail... */
            PL_reg_oldsaved = prog->subbeg;
            PL_reg_oldsavedlen = prog->sublen;
                $` inside (?{}) could fail... */
            PL_reg_oldsaved = prog->subbeg;
            PL_reg_oldsavedlen = prog->sublen;
+#ifdef PERL_COPY_ON_WRITE
+           PL_nrs = prog->saved_copy;
+#endif
            RX_MATCH_COPIED_off(prog);
        }
        else
            RX_MATCH_COPIED_off(prog);
        }
        else
@@ -2107,6 +2173,7 @@ S_regtry(pTHX_ regexp *prog, char *startpos)
     PL_reglastparen = &prog->lastparen;
     PL_reglastcloseparen = &prog->lastcloseparen;
     prog->lastparen = 0;
     PL_reglastparen = &prog->lastparen;
     PL_reglastcloseparen = &prog->lastcloseparen;
     prog->lastparen = 0;
+    prog->lastcloseparen = 0;
     PL_regsize = 0;
     DEBUG_r(PL_reg_starttry = startpos);
     if (PL_reg_start_tmpl <= prog->nparens) {
     PL_regsize = 0;
     DEBUG_r(PL_reg_starttry = startpos);
     if (PL_reg_start_tmpl <= prog->nparens) {
@@ -2269,17 +2336,17 @@ S_regmatch(pTHX_ regnode *prog)
            regprop(prop, scan);
            {
              char *s0 =
            regprop(prop, scan);
            {
              char *s0 =
-               do_utf8 ?
+               do_utf8 && OP(scan) != CANY ?
                pv_uni_display(dsv0, (U8*)(locinput - pref_len),
                               pref0_len, 60, UNI_DISPLAY_REGEX) :
                locinput - pref_len;
              int len0 = do_utf8 ? strlen(s0) : pref0_len;
                pv_uni_display(dsv0, (U8*)(locinput - pref_len),
                               pref0_len, 60, UNI_DISPLAY_REGEX) :
                locinput - pref_len;
              int len0 = do_utf8 ? strlen(s0) : pref0_len;
-             char *s1 = do_utf8 ?
+             char *s1 = do_utf8 && OP(scan) != CANY ?
                pv_uni_display(dsv1, (U8*)(locinput - pref_len + pref0_len),
                               pref_len - pref0_len, 60, UNI_DISPLAY_REGEX) :
                locinput - pref_len + pref0_len;
              int len1 = do_utf8 ? strlen(s1) : pref_len - pref0_len;
                pv_uni_display(dsv1, (U8*)(locinput - pref_len + pref0_len),
                               pref_len - pref0_len, 60, UNI_DISPLAY_REGEX) :
                locinput - pref_len + pref0_len;
              int len1 = do_utf8 ? strlen(s1) : pref_len - pref0_len;
-             char *s2 = do_utf8 ?
+             char *s2 = do_utf8 && OP(scan) != CANY ?
                pv_uni_display(dsv2, (U8*)locinput,
                               PL_regeol - locinput, 60, UNI_DISPLAY_REGEX) :
                locinput;
                pv_uni_display(dsv2, (U8*)locinput,
                               PL_regeol - locinput, 60, UNI_DISPLAY_REGEX) :
                locinput;
@@ -2310,8 +2377,7 @@ S_regmatch(pTHX_ regnode *prog)
 
        switch (OP(scan)) {
        case BOL:
 
        switch (OP(scan)) {
        case BOL:
-           if (locinput == PL_bostr || (PL_multiline &&
-               (nextchr || locinput < PL_regeol) && locinput[-1] == '\n') )
+           if (locinput == PL_bostr)
            {
                /* regtill = regbol; */
                break;
            {
                /* regtill = regbol; */
                break;
@@ -2333,12 +2399,8 @@ S_regmatch(pTHX_ regnode *prog)
                break;
            sayNO;
        case EOL:
                break;
            sayNO;
        case EOL:
-           if (PL_multiline)
-               goto meol;
-           else
                goto seol;
        case MEOL:
                goto seol;
        case MEOL:
-         meol:
            if ((nextchr || locinput < PL_regeol) && nextchr != '\n')
                sayNO;
            break;
            if ((nextchr || locinput < PL_regeol) && nextchr != '\n')
                sayNO;
            break;
@@ -2791,13 +2853,14 @@ S_regmatch(pTHX_ regnode *prog)
            dSP;
            OP_4tree *oop = PL_op;
            COP *ocurcop = PL_curcop;
            dSP;
            OP_4tree *oop = PL_op;
            COP *ocurcop = PL_curcop;
-           SV **ocurpad = PL_curpad;
+           PAD *old_comppad;
            SV *ret;
            SV *ret;
+           struct regexp *oreg = PL_reg_re;
        
            n = ARG(scan);
            PL_op = (OP_4tree*)PL_regdata->data[n];
            DEBUG_r( PerlIO_printf(Perl_debug_log, "  re_eval 0x%"UVxf"\n", PTR2UV(PL_op)) );
        
            n = ARG(scan);
            PL_op = (OP_4tree*)PL_regdata->data[n];
            DEBUG_r( PerlIO_printf(Perl_debug_log, "  re_eval 0x%"UVxf"\n", PTR2UV(PL_op)) );
-           PL_curpad = AvARRAY((AV*)PL_regdata->data[n + 2]);
+           PAD_SAVE_LOCAL(old_comppad, (PAD*)PL_regdata->data[n + 2]);
            PL_regendp[0] = PL_reg_magic->mg_len = locinput - PL_bostr;
 
            {
            PL_regendp[0] = PL_reg_magic->mg_len = locinput - PL_bostr;
 
            {
@@ -2805,7 +2868,7 @@ S_regmatch(pTHX_ regnode *prog)
                CALLRUNOPS(aTHX);                       /* Scalar context. */
                SPAGAIN;
                if (SP == before)
                CALLRUNOPS(aTHX);                       /* Scalar context. */
                SPAGAIN;
                if (SP == before)
-                   ret = Nullsv;   /* protect against empty (?{}) blocks. */
+                   ret = &PL_sv_undef;   /* protect against empty (?{}) blocks. */
                else {
                    ret = POPs;
                    PUTBACK;
                else {
                    ret = POPs;
                    PUTBACK;
@@ -2813,7 +2876,7 @@ S_regmatch(pTHX_ regnode *prog)
            }
 
            PL_op = oop;
            }
 
            PL_op = oop;
-           PL_curpad = ocurpad;
+           PAD_RESTORE_LOCAL(old_comppad);
            PL_curcop = ocurcop;
            if (logical) {
                if (logical == 2) {     /* Postponed subexpression. */
            PL_curcop = ocurcop;
            if (logical) {
                if (logical == 2) {     /* Postponed subexpression. */
@@ -2821,13 +2884,18 @@ S_regmatch(pTHX_ regnode *prog)
                    MAGIC *mg = Null(MAGIC*);
                    re_cc_state state;
                    CHECKPOINT cp, lastcp;
                    MAGIC *mg = Null(MAGIC*);
                    re_cc_state state;
                    CHECKPOINT cp, lastcp;
-
-                   if(SvROK(ret) || SvRMAGICAL(ret)) {
-                       SV *sv = SvROK(ret) ? SvRV(ret) : ret;
-
-                       if(SvMAGICAL(sv))
-                           mg = mg_find(sv, PERL_MAGIC_qr);
+                    int toggleutf;
+                   register SV *sv;
+
+                   if(SvROK(ret) && SvSMAGICAL(sv = SvRV(ret)))
+                       mg = mg_find(sv, PERL_MAGIC_qr);
+                   else if (SvSMAGICAL(ret)) {
+                       if (SvGMAGICAL(ret))
+                           sv_unmagic(ret, PERL_MAGIC_qr);
+                       else
+                           mg = mg_find(ret, PERL_MAGIC_qr);
                    }
                    }
+
                    if (mg) {
                        re = (regexp *)mg->mg_obj;
                        (void)ReREFCNT_inc(re);
                    if (mg) {
                        re = (regexp *)mg->mg_obj;
                        (void)ReREFCNT_inc(re);
@@ -2841,9 +2909,11 @@ S_regmatch(pTHX_ regnode *prog)
                        I32 onpar = PL_regnpar;
 
                        Zero(&pm, 1, PMOP);
                        I32 onpar = PL_regnpar;
 
                        Zero(&pm, 1, PMOP);
+                        if (DO_UTF8(ret)) pm.op_pmdynflags |= PMdf_DYN_UTF8;
                        re = CALLREGCOMP(aTHX_ t, t + len, &pm);
                        if (!(SvFLAGS(ret)
                        re = CALLREGCOMP(aTHX_ t, t + len, &pm);
                        if (!(SvFLAGS(ret)
-                             & (SVs_TEMP | SVs_PADTMP | SVf_READONLY)))
+                             & (SVs_TEMP | SVs_PADTMP | SVf_READONLY
+                               | SVs_GMG)))
                            sv_magic(ret,(SV*)ReREFCNT_inc(re),
                                        PERL_MAGIC_qr,0,0);
                        PL_regprecomp = oprecomp;
                            sv_magic(ret,(SV*)ReREFCNT_inc(re),
                                        PERL_MAGIC_qr,0,0);
                        PL_regprecomp = oprecomp;
@@ -2873,6 +2943,9 @@ S_regmatch(pTHX_ regnode *prog)
                    *PL_reglastcloseparen = 0;
                    PL_reg_call_cc = &state;
                    PL_reginput = locinput;
                    *PL_reglastcloseparen = 0;
                    PL_reg_call_cc = &state;
                    PL_reginput = locinput;
+                   toggleutf = ((PL_reg_flags & RF_utf8) != 0) ^
+                               ((re->reganch & ROPT_UTF8) != 0);
+                   if (toggleutf) PL_reg_flags ^= RF_utf8;
 
                    /* XXXX This is too dramatic a measure... */
                    PL_reg_maxiter = 0;
 
                    /* XXXX This is too dramatic a measure... */
                    PL_reg_maxiter = 0;
@@ -2887,6 +2960,7 @@ S_regmatch(pTHX_ regnode *prog)
                        PL_regcc = state.cc;
                        PL_reg_re = state.re;
                        cache_re(PL_reg_re);
                        PL_regcc = state.cc;
                        PL_reg_re = state.re;
                        cache_re(PL_reg_re);
+                       if (toggleutf) PL_reg_flags ^= RF_utf8;
 
                        /* XXXX This is too dramatic a measure... */
                        PL_reg_maxiter = 0;
 
                        /* XXXX This is too dramatic a measure... */
                        PL_reg_maxiter = 0;
@@ -2903,6 +2977,7 @@ S_regmatch(pTHX_ regnode *prog)
                    PL_regcc = state.cc;
                    PL_reg_re = state.re;
                    cache_re(PL_reg_re);
                    PL_regcc = state.cc;
                    PL_reg_re = state.re;
                    cache_re(PL_reg_re);
+                   if (toggleutf) PL_reg_flags ^= RF_utf8;
 
                    /* XXXX This is too dramatic a measure... */
                    PL_reg_maxiter = 0;
 
                    /* XXXX This is too dramatic a measure... */
                    PL_reg_maxiter = 0;
@@ -2913,8 +2988,10 @@ S_regmatch(pTHX_ regnode *prog)
                sw = SvTRUE(ret);
                logical = 0;
            }
                sw = SvTRUE(ret);
                logical = 0;
            }
-           else
+           else {
                sv_setsv(save_scalar(PL_replgv), ret);
                sv_setsv(save_scalar(PL_replgv), ret);
+               cache_re(oreg);
+           }
            break;
        }
        case OPEN:
            break;
        }
        case OPEN:
@@ -3147,7 +3224,10 @@ S_regmatch(pTHX_ regnode *prog)
                                      "%*s  already tried at this position...\n",
                                      REPORT_CODE_OFF+PL_regindent*2, "")
                        );
                                      "%*s  already tried at this position...\n",
                                      REPORT_CODE_OFF+PL_regindent*2, "")
                        );
-                       sayNO_SILENT;
+                       if (PL_reg_flags & RF_false)
+                           sayYES;
+                       else
+                           sayNO_SILENT;
                    }
                    PL_reg_poscache[o] |= (1<<b);
                }
                    }
                    PL_reg_poscache[o] |= (1<<b);
                }
@@ -3296,7 +3376,7 @@ S_regmatch(pTHX_ regnode *prog)
            CHECKPOINT lastcp;
        
            /* We suppose that the next guy does not need
            CHECKPOINT lastcp;
        
            /* We suppose that the next guy does not need
-              backtracking: in particular, it is of constant length,
+              backtracking: in particular, it is of constant non-zero length,
               and has no parenths to influence future backrefs. */
            ln = ARG1(scan);  /* min to match */
            n  = ARG2(scan);  /* max to match */
               and has no parenths to influence future backrefs. */
            ln = ARG1(scan);  /* min to match */
            n  = ARG2(scan);  /* max to match */
@@ -3315,15 +3395,6 @@ S_regmatch(pTHX_ regnode *prog)
                minmod = 0;
                if (ln && regrepeat_hard(scan, ln, &l) < ln)
                    sayNO;
                minmod = 0;
                if (ln && regrepeat_hard(scan, ln, &l) < ln)
                    sayNO;
-               /* if we matched something zero-length we don't need to
-                  backtrack - capturing parens are already defined, so
-                  the caveat in the maximal case doesn't apply
-
-                  XXXX if ln == 0, we can redo this check first time
-                  through the following loop
-               */
-               if (ln && l == 0)
-                   n = ln;     /* don't backtrack */
                locinput = PL_reginput;
                if (HAS_TEXT(next) || JUMPABLE(next)) {
                    regnode *text_node = next;
                locinput = PL_reginput;
                if (HAS_TEXT(next) || JUMPABLE(next)) {
                    regnode *text_node = next;
@@ -3333,19 +3404,8 @@ S_regmatch(pTHX_ regnode *prog)
                    if (! HAS_TEXT(text_node)) c1 = c2 = -1000;
                    else {
                        if (PL_regkind[(U8)OP(text_node)] == REF) {
                    if (! HAS_TEXT(text_node)) c1 = c2 = -1000;
                    else {
                        if (PL_regkind[(U8)OP(text_node)] == REF) {
-                           I32 n, ln;
-                           n = ARG(text_node);  /* which paren pair */
-                           ln = PL_regstartp[n];
-                           /* assume yes if we haven't seen CLOSEn */
-                           if (
-                               (I32)*PL_reglastparen < n ||
-                               ln == -1 ||
-                               ln == PL_regendp[n]
-                           ) {
-                               c1 = c2 = -1000;
-                               goto assume_ok_MM;
-                           }
-                           c1 = *(PL_bostr + ln);
+                           c1 = c2 = -1000;
+                           goto assume_ok_MM;
                        }
                        else { c1 = (U8)*STRING(text_node); }
                        if (OP(text_node) == EXACTF || OP(text_node) == REFF)
                        }
                        else { c1 = (U8)*STRING(text_node); }
                        if (OP(text_node) == EXACTF || OP(text_node) == REFF)
@@ -3360,8 +3420,7 @@ S_regmatch(pTHX_ regnode *prog)
                    c1 = c2 = -1000;
            assume_ok_MM:
                REGCP_SET(lastcp);
                    c1 = c2 = -1000;
            assume_ok_MM:
                REGCP_SET(lastcp);
-               /* This may be improved if l == 0.  */
-               while (n >= ln || (n == REG_INFTY && ln > 0 && l)) { /* ln overflow ? */
+               while (n >= ln || (n == REG_INFTY && ln > 0)) { /* ln overflow ? */
                    /* If it could work, try it. */
                    if (c1 == -1000 ||
                        UCHARAT(PL_reginput) == c1 ||
                    /* If it could work, try it. */
                    if (c1 == -1000 ||
                        UCHARAT(PL_reginput) == c1 ||
@@ -3392,13 +3451,6 @@ S_regmatch(pTHX_ regnode *prog)
            }
            else {
                n = regrepeat_hard(scan, n, &l);
            }
            else {
                n = regrepeat_hard(scan, n, &l);
-               /* if we matched something zero-length we don't need to
-                  backtrack, unless the minimum count is zero and we
-                  are capturing the result - in that case the capture
-                  being defined or not may affect later execution
-               */
-               if (n != 0 && l == 0 && !(paren && ln == 0))
-                   ln = n;     /* don't backtrack */
                locinput = PL_reginput;
                DEBUG_r(
                    PerlIO_printf(Perl_debug_log,
                locinput = PL_reginput;
                DEBUG_r(
                    PerlIO_printf(Perl_debug_log,
@@ -3415,19 +3467,8 @@ S_regmatch(pTHX_ regnode *prog)
                        if (! HAS_TEXT(text_node)) c1 = c2 = -1000;
                        else {
                            if (PL_regkind[(U8)OP(text_node)] == REF) {
                        if (! HAS_TEXT(text_node)) c1 = c2 = -1000;
                        else {
                            if (PL_regkind[(U8)OP(text_node)] == REF) {
-                               I32 n, ln;
-                               n = ARG(text_node);  /* which paren pair */
-                               ln = PL_regstartp[n];
-                               /* assume yes if we haven't seen CLOSEn */
-                               if (
-                                   (I32)*PL_reglastparen < n ||
-                                   ln == -1 ||
-                                   ln == PL_regendp[n]
-                               ) {
-                                   c1 = c2 = -1000;
-                                   goto assume_ok_REG;
-                               }
-                               c1 = *(PL_bostr + ln);
+                               c1 = c2 = -1000;
+                               goto assume_ok_REG;
                            }
                            else { c1 = (U8)*STRING(text_node); }
 
                            }
                            else { c1 = (U8)*STRING(text_node); }
 
@@ -3524,19 +3565,8 @@ S_regmatch(pTHX_ regnode *prog)
                if (! HAS_TEXT(text_node)) c1 = c2 = -1000;
                else {
                    if (PL_regkind[(U8)OP(text_node)] == REF) {
                if (! HAS_TEXT(text_node)) c1 = c2 = -1000;
                else {
                    if (PL_regkind[(U8)OP(text_node)] == REF) {
-                       I32 n, ln;
-                       n = ARG(text_node);  /* which paren pair */
-                       ln = PL_regstartp[n];
-                       /* assume yes if we haven't seen CLOSEn */
-                       if (
-                           (I32)*PL_reglastparen < n ||
-                           ln == -1 ||
-                           ln == PL_regendp[n]
-                       ) {
-                           c1 = c2 = -1000;
-                           goto assume_ok_easy;
-                       }
-                       s = (U8*)PL_bostr + ln;
+                       c1 = c2 = -1000;
+                       goto assume_ok_easy;
                    }
                    else { s = (U8*)STRING(text_node); }
 
                    }
                    else { s = (U8*)STRING(text_node); }
 
@@ -3682,14 +3712,14 @@ S_regmatch(pTHX_ regnode *prog)
                        /* If it could work, try it. */
                        if (c == (UV)c1 || c == (UV)c2)
                        {
                        /* If it could work, try it. */
                        if (c == (UV)c1 || c == (UV)c2)
                        {
-                           TRYPAREN(paren, n, PL_reginput);
+                           TRYPAREN(paren, ln, PL_reginput);
                            REGCP_UNWIND(lastcp);
                        }
                    }
                    /* If it could work, try it. */
                    else if (c1 == -1000)
                    {
                            REGCP_UNWIND(lastcp);
                        }
                    }
                    /* If it could work, try it. */
                    else if (c1 == -1000)
                    {
-                       TRYPAREN(paren, n, PL_reginput);
+                       TRYPAREN(paren, ln, PL_reginput);
                        REGCP_UNWIND(lastcp);
                    }
                    /* Couldn't or didn't -- move forward. */
                        REGCP_UNWIND(lastcp);
                    }
                    /* Couldn't or didn't -- move forward. */
@@ -3707,7 +3737,7 @@ S_regmatch(pTHX_ regnode *prog)
                n = regrepeat(scan, n);
                locinput = PL_reginput;
                if (ln < n && PL_regkind[(U8)OP(next)] == EOL &&
                n = regrepeat(scan, n);
                locinput = PL_reginput;
                if (ln < n && PL_regkind[(U8)OP(next)] == EOL &&
-                   ((!PL_multiline && OP(next) != MEOL) ||
+                   (OP(next) != MEOL ||
                        OP(next) == SEOL || OP(next) == EOS))
                {
                    ln = n;                     /* why back off? */
                        OP(next) == SEOL || OP(next) == EOS))
                {
                    ln = n;                     /* why back off? */
@@ -3830,6 +3860,7 @@ S_regmatch(pTHX_ regnode *prog)
            }
            else
                PL_reginput = locinput;
            }
            else
                PL_reginput = locinput;
+           PL_reg_flags ^= RF_false;
            goto do_ifmatch;
        case IFMATCH:
            n = 1;
            goto do_ifmatch;
        case IFMATCH:
            n = 1;
@@ -3845,6 +3876,8 @@ S_regmatch(pTHX_ regnode *prog)
          do_ifmatch:
            inner = NEXTOPER(NEXTOPER(scan));
            if (regmatch(inner) != n) {
          do_ifmatch:
            inner = NEXTOPER(NEXTOPER(scan));
            if (regmatch(inner) != n) {
+               if (n == 0)
+                   PL_reg_flags ^= RF_false;
              say_no:
                if (logical) {
                    logical = 0;
              say_no:
                if (logical) {
                    logical = 0;
@@ -3854,6 +3887,8 @@ S_regmatch(pTHX_ regnode *prog)
                else
                    sayNO;
            }
                else
                    sayNO;
            }
+           if (n == 0)
+               PL_reg_flags ^= RF_false;
          say_yes:
            if (logical) {
                logical = 0;
          say_yes:
            if (logical) {
                logical = 0;
@@ -4220,7 +4255,7 @@ S_regrepeat(pTHX_ regnode *p, I32 max)
 /*
  - regrepeat_hard - repeatedly match something, report total lenth and length
  *
 /*
  - regrepeat_hard - repeatedly match something, report total lenth and length
  *
- * The repeater is supposed to have constant length.
+ * The repeater is supposed to have constant non-zero length.
  */
 
 STATIC I32
  */
 
 STATIC I32
@@ -4331,13 +4366,12 @@ S_reginclass(pTHX_ register regnode *n, register U8* p, STRLEN* lenp, register b
     char flags = ANYOF_FLAGS(n);
     bool match = FALSE;
     UV c = *p;
     char flags = ANYOF_FLAGS(n);
     bool match = FALSE;
     UV c = *p;
-    STRLEN len = 1;
+    STRLEN len = 0;
     STRLEN plen;
 
     STRLEN plen;
 
-    c = (do_utf8 && !UTF8_IS_INVARIANT(c)) ?
-        utf8n_to_uvchr(p, UTF8_MAXLEN, &len,
-                       ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY) :
-         NATIVE_TO_UTF(c);
+    if (do_utf8 && !UTF8_IS_INVARIANT(c))
+        c = utf8n_to_uvchr(p, UTF8_MAXLEN, &len,
+                           ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY);
 
     plen = lenp ? *lenp : UNISKIP(NATIVE_TO_UNI(c));
     if (do_utf8 || (flags & ANYOF_UNICODE)) {
 
     plen = lenp ? *lenp : UNISKIP(NATIVE_TO_UNI(c));
     if (do_utf8 || (flags & ANYOF_UNICODE)) {
@@ -4518,6 +4552,9 @@ restore_pos(pTHX_ void *arg)
        if (PL_reg_oldsaved) {
            PL_reg_re->subbeg = PL_reg_oldsaved;
            PL_reg_re->sublen = PL_reg_oldsavedlen;
        if (PL_reg_oldsaved) {
            PL_reg_re->subbeg = PL_reg_oldsaved;
            PL_reg_re->sublen = PL_reg_oldsavedlen;
+#ifdef PERL_COPY_ON_WRITE
+           PL_reg_re->saved_copy = PL_nrs;
+#endif
            RX_MATCH_COPIED_on(PL_reg_re);
        }
        PL_reg_magic->mg_len = PL_reg_oldpos;
            RX_MATCH_COPIED_on(PL_reg_re);
        }
        PL_reg_magic->mg_len = PL_reg_oldpos;
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